Attempt to determine the effect of family size and childspacing upon the health and social development of children and their mothers using a population (drawn from a Danish Perinatal study) consisting of 9,006 children born between 1959 and 1961 at the University Hospital in Copenhagen, Denmark. The project comprises of three major studies: a study of familial and maternal factors on child outcomes at birth and at one year; a study of familial and maternal factors on child outcomes at 16-18 years of age, using a 10% of the original perinatal sample; and a study of familian and maternal factors on long-term mother outcomes in the sample cohort, in an attempt to analyze the consequences of childbearing patterns in terms of health, career, marital happiness, divorce, etc.